PhD proposal : Computational Brain Growth Modeling
Lab: LSIS & INT, Marseille France
Starting date : Fall 2017
Funding : FRM (Fédération pour la recherche médicale)
With a prevalence of 1/2,000 to 1/4,000 live births, perinatal ischemic stroke is the most frequent form of childhood stroke and constitutes the leading cause of unilateral cerebral palsy in term-born children. Perinatal ischemic stroke is an umbrella term including several conditions that differ in pathophysiology, timing and thus in outcomes. Neonatal arterial ischemic stroke (NAIS) refers to a perinatal ischemic stroke syndrome with neonatal signs (mainly iterative focal seizures in the first days of life) related to an arterial infarct as revealed by brain imaging.
Every case of NAIS is unique to the individual. Considering for instance NAIS leading to unilateral cerebral palsy, one person may have total paralysis and require constant care, while another with partial paralysis might have slight movement tremors but require little assistance. This is due in part to the type of injury and the timing of the injury to the developing brain. The prediction of long-term motor outcome (and the associated treatment or therapy) requires new personalized approaches, i.e. patient-specific techniques to understand the causes of the observed disabilities.
The first objective of this PhD is to provide a temporal brain map of tangential expansion ratio of the cortical layer relative to the white matter. In our previous work, fixed values of the cortical thickness and the tangential growth have been used. This simplification may be too restrictive to provide personalized simulation of brain growth. It is expected that this growth rate varies temporally and spatially (i.e. each brain region has intrinsic growth dynamics). An in vivo observation-constrained physical model of brain growth will be developed to estimate realistic temporal maps of the tangential growth. The developed method will rely on an inverse problem formulation linking the simulated growth with temporal fetal brain template. The goal is to estimate locally the best tangential growth rate making the physical simulation of brain surface evolution fitting with mean temporal MRI data.
The second objective focuses on the introduction of diffusion MRI-based information into the physical model. Tangential cortical expansion is clearly a key process in cortical folding, but it must be coupled with radial growth. Tangential growth is indeed closely related to radial growth. The generation of intermediate radial glia cells plays a key role in the tangential expansion of the cerebral. More specifically, the intermediate radial glial cells creates a fan-shaped, expanding network of radial glial fibers that enables rapid tangential expansion of the cortex in folded brains.
Candidates are invited to email (to Julien Lefèvre, François Rousseau, and Mickaël Dinomais) a motivation letter and CV detailing in full your academic background, including all modules taken and grades assigned.
(c) GdR 720 ISIS - CNRS - 2011-2015.